The importance (?) of lowering high TA

[ddas]

I've got very high TA (120) but am a little confused by the directions here:

http://www.troublefreepool.com/content/129-how-to-lower-lowering-total-alkalinity

It seems to hint that if I don't have those problems, no need to correct them. Well, should I or shouldn't I? What are the downsides of high TA? (Please feel free to point me to a Pool School post if I missed it.)

(Other test results for the record: FAC: 12 because I'm in the middle of eradicating a small algae outgrowth, CYA = 60, TA = 120, pH = 8.0).

Maybe related: my pH is constantly drifting upwards. I check it once a month (or so) and it always drifts up to around 8.0 so I'm constantly adding muriatic acid once a month to tamp it down to the 7.4-7.5 range.

 

[jblizzle]

First, that TA is not very high.
Second, it is not that important to worry about it.
It is more important to maintain the pH in range and the the TA will lower itself as you do so.

Third, adding acid once a month is not very often ... although I would suggest testing it a little more often.

 

[pwrstrk]

If your adding acid only once a month I don't think thats often. If you had to to add it 3 - 4 times a week I would say that's often. The TA is in a good place when you have a slow increase in PH which seems to be your case.
The TA maybe be out of range on paper but if your PH is pretty stable I would leave it alone. ?

 

[ddas]

Hmmm. OK. pH doesn't seem stable when I check it once a month and it always drifts up into 8.0+.

But -- advice taken -- I will check pH more regularly, and maybe add smaller quantities of muriatic acid more regularly so as to keep the pH lower. Thanks for the advice on not worrying too much about the TA for now.

Once I get good at this, I'm hoping to have a better feel for the average maintenance my pool needs (e.g. add x amount of muriatic per week, add x amount of liquid chlorine per week) so I can keep it roughly in range, without having to test constantly.

 

[pwrstrk]

Do you happen to know what your CH is ?

 

[ddas]

Interesting question. I just tried to test today (because I know my water is really hard) but the test did something weird. It was supposed to turn one color, but instead turned colorless. Wondering if I did something wrong. I may go to Leslie's tomorrow to see if they can help me test CH. Will report back. But short answer: I know it's very high.

 

[pwrstrk]

If you know it's very high you want to keep that PH in check or you'll run the risk of scaling. All the reason to test PH more often than once a month.
I still think your TA is ok though. I'm not sure about your CH test. ?

 

[jblizzle]

With a SWG and water feature, some people have to adjust the pH every few days.

 

[ddas]

Hmmm, OK, thanks for that tip (which I had forgotten from Pool School). I'll keep a closer eye on my pH regularly then, and will try and retest or get help figuring out my calcium hardness, and report back once I get a grip on those two.

 

[Smykowski]

But -- advice taken -- I will check pH more regularly, and maybe add smaller quantities of muriatic acid more regularly so as to keep the pH lower. Thanks for the advice on not worrying too much about the TA for now.

And if you do this, TA will naturally drop, which will slow the pH rise, which will require less frequent acid additions....

It was said before, but I'm saying it again to emphasize the point: in your case, keep the pH in range and the TA will take care of itself.

 

[JasonLion]

If the CH test initially turned a color, and then as you added drops it turned colorless, the result is still valid. If it never turned a color in the first place the results are not valid.

 

[anonapersona]

My tap water has high TA, sometimes 340, sometimes 220, so if I have to add much fill water the pool TA can get high enough to continually push pH up to 8.0 as you are seeing. So when I test (right now 2x/week as pool is still cold, later I will test 3x/week) I test both FC and pH and I test TA every week or two.

When TA is above 100 I will adjust the pH of the pool a bit more, pushing it down to 7.2 so the TA is pushed down a bit as well. You do want to test TA if you are trying to adjust it because TA is directly related to the effect of acid on pH. That is, if the TA is lower than you thought, you may add more acid than you need and get more pH change than you desired. So test TA before you adjust pH by much.

Once in a great while I have gotten the TA to 60 where the pH suddenly becomes quite stable, in spite of the spa spillover and waterfall. But, if I need to use tablets in the feeder while I am off on a trip then I need to have the TA up at about 100 because of the acid included in the tablets. So, I tend to just make peace with the TA staying in the 80-120 range. My pool normally takes a gallon of 10% chlorine and 3 cups of acid, every 2nd or 3rd day depending on the season.